The invention relates to a tuner for cavity resonators by the controlled, non-destructive deformation of stiff hollow bodies, especially for adjusting the oscillation frequency of superconducting resonators.
A tuner for cavity resonators is already known, for which one or several geared spindle drives, which compress or extend the resonator (Tesla Report No. 96-09, Deutsches Elektronen-Synchrotron Hamburg, page 2: Proceedings of the CERN Accelerator School No. 89-04, 30.5-3.6. 1988, pages 224-226 CERN, Geneva), and are coupled mechanically in the same direction, are disposed about the effective axis.
It is also known that a one-stage or multi-stage lever mechanism, which is moved by a geared spindle drive, may be used (Proceedings of the 2nd Workshop on Rf Superconductivity, Jul. 23 to 27, 1984, Part 1, page 85, CERN, Geneva).
Furthermore, a construction is known, for which the load arm engages the front side of the resonator, while all lever fulcrums are connected with the rear side of the resonator (Tesla Report No. 95-01, Deutsches Elektronen-Synchrotron Hamburg, page 174).
In such mechanical gearings, different rotary bearings, provided with sliding layers, are used, which can be operated only in a very expensive construction and with very expensive maintenance, especially in a vacuum and at a temperature close to absolute zero. Under the conditions of use named, these bearings do not attain the required service life and absence of play.
If appropriately constructed, a piezostrictive driving mechanism can attain the required resolution, but not, at the same time, the required large displacement path and a high driving force. Such driving mechanisms are therefore frequently connected downstream from a coarsely working mechanical driving mechanism (Proceedings of the CERN Accelerator School No. 89-04, 30.5-3.6. 1988, page 174, CERN, Geneva). At the same time, the costs and the space required increase. Over the operating time of this driving mechanism, the driving energy must be maintained constantly and kept extremely constant. The inherent hysteresis also has a disadvantageous effect on the operation of such a driving mechanism. The tuning result is lost when the driving energy is switched off. Because of the decreasing effect and the mechanical unreliability, the use of piezostrictive driving mechanisms at temperatures close to absolute zero is not possible.
A magnetostrictive driving mechanism is also known (Proceedings of the 6th Workshop on Rf superconductivity, Oct. 4th to 8th, 1993, vol. 2, page 1074, CERN, Geneva). This driving mechanism requires a large structural length for producing the required adjustment path. Several such driving mechanisms must be connected in parallel in order to produce simultaneously the high adjusting force that is required. Since the characteristic action lines deviate from one another, there is an additional expense for adapting the characteristic lines when such driving mechanisms are connected in parallel. The self-magnetic field of such driving mechanisms interferes with the behavior of the suprconducting resonators. Here also, for the time that this driving mechanism is working, the driving energy must be maintained constantly and kept extremely constant and the tuning result is lost when the driving energy is switched off.
It is therefore an object of the invention to propose a mechanical gearing for a tuner for cavity resonators, which can be realized and operated in a less expensive version and the long service life and little backlash of which are assured even at very low temperatures. At the same time, the piezoelectric or magnetostrictive driving mechanisms or their combinations with coarse driving mechanisms shall be omitted.
Pursuant to the invention, the objective is accomplished with a first lever member mounted to effect movement of a resonator, having an arm; a second lever member pivotably connected to the resonator; and a torsoinal deflecting member connecting said first lever member and said second lever member.
Aside from the objectives listed, a regulating distance of a few tenth of a millimeter with a resolution of about a few nanometers at a regulating power of more than 2,000 N can be attained reproducibly with the use of the invention and the tuning position is retained even after the driving energy is switched off. These conditions are maintained even in little space.